One of the best short - term stock market indicators is the so-called "CBOE Options Total Put / Call ratio".
According to Investopedia:
The put-call ratio is a ratio of the trading volume of put options to call options. The put-call ratio has long been viewed as an indicator of investor sentiment in the markets. Times where the number of traded call options outpaces the number of traded put options would signal a bullish sentiment, and vice versa.
The chart below shows this ratio:
Yesterday the ratio was below 1.0 (actually 0.77) so the number of traded call options was outpacing the number of put options. It is an indication of extreme (in the short - term) bullishness among the players.
As the chart shows (red circles), when the ratio was standing at these levels, equities were ahead of a substantial drop in their prices.
Note: the chart shows historic data (the last reading was on March 3, 2016). Today equities are still going up so, I guess, the indicator is even below 0.77.